Description

Congenital muscular dystrophies (DMC) represent a heterogeneous group of genetically derived, mainly autosomal recessive, myopathies. They have in common an onset before 1 year of life, essentially characterized by a hypotonia with muscular hyposthenia, responsible for a delay and disorders of motor autonomy. Orthopedic and respiratory manifestations, more or less serious, early and evolutionary, are the main consequences of muscle injury. Some DMCs, in particular dystroglycanopathies, show signs of involvement of the central nervous system (psychomotor retardation, encephalopathy, etc.) which are in the foreground. The narrow anatomical definition of RCDs, based on histological analysis of skeletal muscle, tends to fade to the advantage of molecular data. The latter allow us to distinguish four groups of DMC: DMC by mutation of a protein of basement membrane structure or of the extracellular matrix of skeletal muscle fibers (merosine deficiency [MDC1A], Ullrich syndrome due to collagen VI mutation [UCMD], deficit of integrin alfa 7), DMC by mutation of a glycosyltransferase of alpha-dystroglycan or dystroglycanopathy (Fukuyama disease [FCMD], muscle-eye-brain syndrome [MEB], Walker-Warburg syndrome [WWS], MDC1C, MDC1D), other forms of genetically characterized DMC (mutation of the selenoprotein N1 gene [RSMD1], mutation of the laminar gene A / C [L-CMD]) and DMC in which the gene has not yet been identified. By order of frequency, the two major diseases are DMC due to merosine deficiency and Ullrich syndrome. The diagnostic procedure of a DMC must be extremely rigorous. The presence or absence of clinical signs of involvement of the central nervous system, the rate of plasma creatine kinases and the analysis of merosin and alpha-dystroglycan proteins starting from muscle biopsy represent the first inevitable stages. It is therefore necessary to discuss the interest of brain magnetic resonance (MRI), muscle MRI and fibroblast culture to target the molecular investigation that allows confirmation of diagnosis and genetic counseling.

External Information

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